diff --git a/src/tint2conf/main.c b/src/tint2conf/main.c
index fdff45e..bcb81ae 100644
--- a/src/tint2conf/main.c
+++ b/src/tint2conf/main.c
@@ -100,7 +100,7 @@ char *file_name_from_path(const char *filepath)
 
 void make_backup(const char *filepath)
 {
-    gchar *backup_path = g_strdup_printf("%s.backup.%ld", filepath, (long)time(NULL));
+    gchar *backup_path = g_strdup_printf("%s.backup.%lld", filepath, (long long)time(NULL));
     copy_file(filepath, backup_path);
     g_free(backup_path);
 }
diff --git a/src/tint2conf/properties.c b/src/tint2conf/properties.c
index d028f21..1f5961b 100644
--- a/src/tint2conf/properties.c
+++ b/src/tint2conf/properties.c
@@ -181,7 +181,7 @@ void applyClicked(GtkWidget *widget, gpointer data)
     gchar *filepath = get_current_theme_path();
     if (filepath) {
         if (config_is_manual(filepath)) {
-            gchar *backup_path = g_strdup_printf("%s.backup.%ld", filepath, (long)time(NULL));
+            gchar *backup_path = g_strdup_printf("%s.backup.%lld", filepath, (long long)time(NULL));
             copy_file(filepath, backup_path);
             g_free(backup_path);
         }